MC34166 ON Semiconductor, MC34166 Datasheet - Page 8

• Manufacturer Part Number: MC34166
• Description: (MC33166 / MC34166) Step-Up/Down/Inverting Switching Regulators
• Manufacturer: ON Semiconductor

equivalent Schottky barrier rectifier is recommended to fulfill
these requirements.
Undervoltage Lockout
incorporated to guarantee that the integrated circuit is fully
functional before the output stage is enabled. The internal
5.05 V reference is monitored by the comparator which
enables the output stage when V
erratic output switching as the threshold is crossed, 0.9 V of
hysteresis is provided.
or plug−in prototype boards. Special care should be taken
to separate ground paths from signal currents and ground
paths from load currents. All high current loops should be
kept as short as possible using heavy copper runs to minimize
ringing and radiated EMI. For best operation, a tight
An Undervoltage Lockout comparator has been
Do not attempt to construct a converter on wire−wrap
I = Standby Mode
Figure 16. Low Power Standby Circuit
Compensation
100 mA
+
120
5
CC
Error
Amp
exceeds 5.9 V. To prevent
V
in
Compensation
1.0 M
DESIGN CONSIDERATIONS
D
Figure 18. Soft−Start Circuit
2
t
100 mA
Soft−Start
1
MC34166, MC33166
http://onsemi.com
R
≈ 35,000 C
1
+
120
5
D
C
1
ss
8
ss
Error
Amp
Thermal Protection
the integrated circuit in the event that the maximum junction
temperature is exceeded. When activated, typically at 170°C,
the latch is forced into a ‘reset’ state, disabling the output
switch. This feature is provided to prevent catastrophic
failures from accidental device overheating. It is not
intended to be used as a substitute for proper heatsinking.
The MC34166 is contained in a 5−lead TO−220 type package.
The tab of the package is common with the center pin (Pin 3)
and is normally connected to ground.
component layout is recommended. Capacitors C
all feedback components should be placed as close to the IC
as physically possible. It is also imperative that the Schottky
diode connected to the Switch Output be located as close to
the IC as possible.
Internal Thermal Shutdown circuitry is provided to protect
Figure 17. Over Voltage Shutdown Circuit
Compensation
V
Shutdown
1
100 mA
= V
R
1
Zener
+
120
5
+ 0.7
Error
Amp
1
IN
, C
R
O
1
, and